why phenol red lactose broth tubes are used for water quality testing

False.

12 grams of carbon-12 constitutes 1 mole of carbon. 1 mole of any substance contains Avogadro number of particles.

A mole is a unit of measurement in chemistry.

one mole of something is equal to as many of that something as there are atoms in 12 grams of the isotope carbon-12.

Avogadro’s wide variety, the wide variety of gadgets in a single mole of any substance (described as its molecular weight in grams), is the same as 6.02214076 × 1023. The gadgets can be electrons, atoms, ions, or molecules, relying on the character of the substance and the individual of the reaction.

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Answer: False

Explanation: Did the exam

The concentration of the diluted HCl solution is 0.363 M, rounded to 3 decimal places.

When a stock solution is diluted, the number of moles of the solute (in this case, HCl) remains constant. We can use the following equation to find the concentration of the diluted solution:

M1V1 = M2V2

where M1 is the initial concentration of the stock solution, V1 is the volume of the stock solution used, M2 is the final concentration of the diluted solution, and V2 is the final volume of the diluted solution.Substituting the given values, we get:

(3.31 M) × (17.5 mL) = M2 × (159 mL)

Solving for M2, we get:

M2 = (3.31 M × 17.5 mL) / 159 mL = 0.363 M.

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Therefore, the molar mass of sodium thiosulfate is: (2 × 22.99 g/mol Na) + (2 × 32.06 g/mol S) + (3 × 16.00 g/mol O) = 158.11 g/mol

The molar mass (gram formula mass) for the compound sodium thiosulfate, Na2S2O3, can be calculated by adding the atomic masses of its constituent elements. The atomic mass of sodium (Na) is 22.99 g/mol, sulfur (S) is 32.06 g/mol, and oxygen (O) is 16.00 g/mol.
It is important to note that molar mass is a crucial concept in chemistry as it helps in determining the amount of substance present in a given sample. Sodium thiosulfate, with its molar mass of 158.11 g/mol, is commonly used as a fixative in photographic processing, in medical applications as an antidote for cyanide poisoning, and as a component in hair products. Its ability to dissolve in water and act as a reducing agent makes it an important compound in many industrial processes as well. Understanding the molar mass of compounds is essential for scientists to conduct experiments accurately and for industries to manufacture products efficiently.

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Answer:

0.159 M (3 s.f.)

Explanation:

This is an acid- base reaction, which is also known as a neutralisation reaction.

\(\boxed{acid \: + base→salt \: + water}\)

1) Write out the balanced chemical equation.

NaOH (aq) +HCl (aq) → NaCl (aq) +H₂O(l)

The equation is balanced as on each side of the equation, there is 1 Na atom, 1 O atom, 2 H atoms and 1 Cl atom.

2) Find the number of moles of NaOH.

The symbol 'M' denotes Molarity, which is the number of moles per litre.

From the given concentration of NaOH,

1 L NaOH ----- 0.450 mol NaOH

Convert 83.0mL to litres:

Volume of NaOH

= 83 ÷1000

= 0.083 L

Moles of NaOH

= 0.083 ×0.450

= 0.03735 mol

3) Find the number of moles of HCl.

From the balanced equation, 1 mole of HCl is needed to neutralize 1 mole of NaOH.

Thus, amount of HCl

= 0.03735 mol

4) Calculate the concentration of HCl

Concentration= mol/ volume

Converting the volume from mL to L,

235 mL= 0.235 L

Concentration of HCl

= 0.03735 ÷0.235

= 0.15894 mol/L (5 s.f.)

= 0.159 M (3 s.f.)

Answer:

by using this formula 2×(n)^२

Answer:

M-A=N

Explanation:

M-A=N

Here is an example.

The equation above means that the atomic number (A) subtracted from the average atomic mass (M) equals the combined amount of neutrons and protons. Since we know that 35 17Cl is Chlorine (this is because Chlorine (Cl) is the 17th number on the periodic table and has the average atomic mass of 35), we can insert our data into the equation and end up with the following:

35-17=18.

From here, we can tell that we have a mix of neutrons and protons, with the total being 18. Since the atomic number is 17, we can reasonably assume that there are 17 protons and 1 neutron.

But we still need to find the number of electrons. Fortunately, the number of electrons is always equivilant to the number of protons and the atomic mass, so we know that the number of electrons is 17.

So, we have;

17 Protons

1 Neutron

17 Electrons

Actually, no. While their mass may be the same (1kg), the volume of lead is a lot smaller than that of feathers. As there is the same mass stuffed in a smaller space, it must be denser. The density of water is 1 g/cm3, so if the density of the lead is more than 1g/cm3, it has to sink

Question

Answer

Explanation

Radio Frequency Is one of the electromagnetic frequency waves that lie in the range stretching from below 3 kilohertz to around 300 gigahertz and which includes the frequencies used for communication signals (such as for radio and television broadcasting and cellular telephone and satellite transmissions)

I hope this helps

The soda in a fridge has more thermal energy than the soda on the kitchen table.

Thermal energy is the total energy possessed by an object due to the motion of its particles. It is directly related to the temperature of the object. When a soda is placed in a fridge, it is exposed to a lower temperature environment. The fridge actively removes heat from the air inside, creating a cooler environment. As a result, the soda's temperature decreases. The decrease in temperature corresponds to a decrease in the average kinetic energy of the soda's particles, which directly affects its thermal energy.

On the other hand, a soda on the kitchen table is exposed to the surrounding room temperature. While the room temperature may vary depending on the location and climate, it is generally higher than the temperature inside a fridge. Consequently, the soda on the kitchen table has a higher temperature, which corresponds to a higher average kinetic energy of its particles and thus a higher thermal energy.

In summary, the soda in a fridge has more thermal energy than the soda on the kitchen table due to the lower temperature environment it is exposed to. The lower temperature corresponds to a decrease in the average kinetic energy of its particles and, consequently, a lower overall thermal energy.

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Answer:

Nickel has a total of 28 electrons.

Explanation:

The percent Ionization of the base is 7.4%.

To solve this problem, we need to first understand what percent ionization means. Percent ionization is the percentage of a weak acid or base that dissociates into ions in water. It is calculated using the formula:

% Ionization = (concentration of ionized form / initial concentration) x 100%

In this case, we are given a 0.43 m solution of a base at 25°C with a pH of 12.80 at equilibrium. We can use the pH value to calculate the concentration of hydroxide ions (OH-) in the solution, which is the ionized form of the base:

pH = 14 - pOH
pOH = 14 - 12.80
pOH = 1.20

[OH-] = 10^-pOH
[OH-] = 10^-1.20
[OH-] = 0.063 mM

Now we can use the concentration of OH- to calculate the percent ionization of the base using the formula above. However, we need to know the initial concentration of the base, which is not given in the problem. Therefore, we need to make an assumption and choose an initial concentration.

Let's assume that the initial concentration of the base is also 0.43 m. We can use the following equation to calculate the concentration of the ionized form of the base (B-):

Kb = ([OH-][B-]) / [BOH]

where Kb is the base dissociation constant, [BOH] is the initial concentration of the base, and [B-] is the concentration of the ionized form of the base.

Kb for the base is not given in the problem, so we cannot calculate [B-] directly. However, we can assume that the base is a weak base, which means that its Kb value is small (less than 1). In this case, we can use the approximation:

[B-] = [OH-]

Plugging in the values we have:

Kb = ([OH-][OH-]) / [BOH]
Kb = (0.063 mM)^2 / 0.43 mM
Kb = 0.0092

Now we can use Kb and the assumption [B-] = [OH-] to calculate the percent ionization:

Kb = (x^2) / (0.43 - x)
0.0092 = (x^2) / (0.43 - x)
x = 0.032 mM

% Ionization = (0.032 mM / 0.43 mM) x 100%
% Ionization = 7.4%

Therefore, the percent ionization of the base is 7.4%.

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It is impossible to reach absolute zero because the magnitude of work that is required to remove energy from a gas in order to attain the absolute zero is so high.

The absolute zero is the temperature at which the movement of all the gas molecules is theoretically believed to cease. At the absolute zero, gas molecules remain at fixed positions because according to the third law of thermodynamics, the entropy of a perfectly ordered system is zero.

It is impossible to reach absolute zero because the magnitude of work that is required to remove energy from a gas in order to attain the absolute zero is so high such that it is impractical to attain the absolute zero.

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Answer:

The correct option is 2.

Explanation:

In a nuclear reaction balanced we have that:

1. The sum of the mass number (A) of the reactants (r) is equal to the sum of the mass number of the products (p) \( \Sigma A_{r} = \Sigma A_{p} \)

2. The sum of the atomic number (Z) of the reactants is also equal to the sum of the atomic number of the products \(\Sigma Z_{r} = \Sigma A_{p}\)      

So, let's evaluate each option.

1) \(^{23}_{11}Na \rightarrow ^{24}_{11}Mg + ^{1}_{1}H\)

The mass number of the reactant is:

\(A_{r} = 23 \)

The sum of the mass number of the products is:

\( A_{p} = 24 + 1 = 25 \)

This is not the correct option because it does not meet the first condition (\( \Sigma A_{r} = \Sigma A_{p}\)).

2) \(^{24}_{11}Na \rightarrow ^{24}_{12}Mg + ^{0}_{-1}e\)  

The mass number of the reactant and the products is:

\(A_{r} = 24 \)

\( A_{p} = 24 + 0 = 24 \)

Now, the atomic number of the reactants and the products are:

\(Z_{r} = 11 \)

\( Z_{p} = 12 + (-1) = 11 \)      

This nuclear reaction is balanced since it does meet the two conditions for a balanced nuclear equation, (\( \Sigma A_{r} = \Sigma A_{p}\) and \( \Sigma Z_{r} = \Sigma Z_{p}\)).  

3) \(^{24}_{13}Al \rightarrow ^{24}_{12}Mg + ^{0}_{-1}e\)      

The mass number of the reactant and the products is:

\(A_{r} = 24 \)

\( A_{p} = 24 + 0 = 24 \)

Now, the atomic number of the reactants and the products are:

\(Z_{r} = 13 \)

\( Z_{p} = 12 + (-1) = 11 \)      

This reaction does not meet the second condition (\( \Sigma Z_{r} = \Sigma Z_{p}\)) so this is not a balanced nuclear equation.

4) \(^{23}_{12}Mg \rightarrow ^{24}_{12}Mg + ^{1}_{0}n\)

The mass number of the reactant and the products is:

\(A_{r} = 23 \)

\( A_{p} = 24 + 1 = 25 \)  

This reaction is not a balanced nuclear equation since it does not meet the first condition (\( \Sigma A_{r} = \Sigma A_{p}\)).

Therefore, the correct option is 2.

I hope it helps you!

Chloric acid has a chemical formula of HClO3. One mole of chloric acid has a molar mass of 84.5 g. Therefore, the mass of 5.3 moles of chloric acid (HClO3) is 448.85 g.

Moles is a unit used to measure the amount of a substance. One mole of a substance is defined as the amount of that substance that contains the same number of atoms, ions, or molecules as there are in 12 grams of carbon-12. The number of particles in one mole of a substance is known as Avogadro’s numbers .The molar mass is the mass of one mole of a substance, and it is calculated by summing the atomic masses of all the atoms in a molecule of that substance. For chloric acid (HClO3), the molar mass is calculated by adding the atomic masses of hydrogen (H), chlorine (Cl), and three oxygen (O) atoms. This gives:1 x 1.01 g/mol (atomic mass of hydrogen) + 1 x 35.45 g/mol (atomic mass of chlorine) + 3 x 16.00 g/mol (atomic mass of oxygen) = 84.5 g/molThe mass of 5.3 moles of chloric acid (HClO3) can be calculated by multiplying the number of moles by the molar mass. This gives:5.3 mol x 84.5 g/mol = 448.85 g

Thus, the mass of 5.3 moles of chloric acid (HClO3) is 448.85 g.

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Answer:

B is correct

Explanation:

pls Brainliest

Answer:

Eddie reeling in a fish that he has caught

Explanation:

Answer:

C: water crops often to wet soil.

Explanation:

Working in the plan industry, it becomes obvious that when watering the plants often, it will pack down the topsoil into the plant. Topsoil is lose at first as stated above, but when enough water gets on it, it becomes almost like mud. This is the kind of topsoil you want. No wind or water will mess it up because it already it watered! It will also help the grow. In addition, plowing is not correct because you only need to plow twice in the plant process. Before you plant the seeds, and to harvest the crops. If you plow to soon and often, you won’t have any plants.

When 45.0 mL of a 1.90 M H₂SO₄ solution is added to 95.0 mL of 0.600 M H₂SO₄the molarity of the resulting solution is 0.95 M.

To answer the question, we need to know what molarity is.

Molarity is the number of moles per unit volume with volume in liters.

To find the molarity of the resulting solution, we need to find the number of moles in each solution.

Number of moles, n = MV where

Given that we have 45.0 mL of a 1.90 M H₂SO₄ solution.

M' = 1.90 M and V' = 45.0 mL = 0.045 L

So, n' = M'V'

= 1.90 M × 0.045 L

= 0.0855 mol

Given that we have 95.0 mL of 0.600 M H₂SO₄ solution.

M" = 0.600 M and V" = 95.0 mL = 0.095 L

So, n" = M"V"

= 0.600 M × 0.095 L

= 0.057 mol

The number of moles in the resulting solution is n'" = n' + n"

= 0.0855 mol + 0.057 mol

= 0.1425 mol

The volume of the resulting solution is V"' = V' + V"

= 45.0 mL + 95.0 mL

= 150.0 mL

= 0.15 L

The molarity of the resulting solution is M'" = n"'/V"'

= 0.1425 mol/0.15 L

= 0.95 mol/L

= 0.95 M

So, the molarity of the resulting solution is 0.95 M.

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Fuel-efficient cars help decrease the global dependency on nonrenewable resources because they use less fuel than other vehicles to travel the same distance.

Nonrenewable resources are natural resources that cannot be readily replaced or regenerated, such as fossil fuels (coal, oil, and natural gas), minerals, and some metals. These resources are finite and once they are used they cannot be replenished. They are formed over millions of years and are essential for the functioning of modern society, but their extraction and use can have negative impacts on the environment.

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Answer:

try t ocopy and paste it

Explanation:

2.56 moles of HCl are required to react with 0.64 moles of KMnO4.

The balanced chemical equation is given as;2KMnO4 + 8HCl → 3Cl2 + 2MnO2 + 4H2O + 2KCl.This equation is balanced in such a way that 2 moles of KMnO4 reacts with 8 moles of HCl to produce 3 moles of Cl2, 2 moles of MnO2, 4 moles of H2O and 2 moles of KCl.We are given the number of moles of KMnO4 as 0.64 moles.Now, we can use stoichiometry to find the number of moles of HCl required to react with 0.64 moles of KMnO4.The balanced chemical equation shows that 8 moles of HCl reacts with 2 moles of KMnO4.

So, one mole of KMnO4 would react with 8/2 = 4 moles of HCl.Now, the number of moles of HCl required to react with 0.64 moles of KMnO4 would be;Moles of HCl = Moles of KMnO4 x (Moles of HCl / Moles of KMnO4) Moles of HCl = 0.64 x 4 = 2.56 moles of HCl.

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Answer:

520mL

Explanation:

Data obtained from the question include:

Molarity of stock solution (M1) = 12M

Volume of stock solution (V1) = 130mL

Molarity of diluted solution (M2) = 3M

Volume of diluted (V2) =..?

The volume of the diluted solution can be obtained as follow:

M1V1 = M2V2

12 x 130 = 3 x V2

Divide both side by 3

V2 = 12 x 130 / 3

V2 = 520mL.

Therefore, 520mL of the diluted solution can be prepared.

The mass of the nitrogen gas is approximately 949 grams.

The mass of the nitrogen gas can be calculated using the ideal gas law, which states:

PV = nRT

Where P is the pressure, V is the volume, n is the number of moles of gas, R is the gas constant, and T is the temperature in Kelvin. R is the ideal gas constant ( 0.08206 Latm/molK )

Given thw volume of the Nitrogen gas to be 759l, at ST, temperature equals 273.15 K and pressure 1 atm.

we can rearrange the ideal gas law to solve for n:

PV = nRT

n = PV / RT

Plug in the values

n = ( 1 atm × 759 L ) / ( 0.08206 Latm/molK × 273.15 K )

n = 33.86 mol

Finally, we can calculate the mass of the nitrogen gas using the molar mass of nitrogen:

m = n × M

Where M = 28.02 g/mol is the molar mass of nitrogen.

m = 33.86 mol × 28.02 g/mol

m = 949 g

Therefore, the mass is 949 g.

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Answer:

the answer is b. 0.452L.

Answer:

0.452L is the answer

Explanation:

The nucleus of the gold atom has a total charge of 1.26 x 10⁻¹⁷ C.

An atom has a nucleus at the center in which subatomic particles like protons and neutrons are present. The electrons revolve around this nucleus in discrete shells.

Neutrons have no charge on them and hence are neutral while protons are positively charged. Therefore the total charge on the nucleus is solely because of the presence of the protons in it.

In terms of magnitude, one proton has +1.6 × 10⁻¹⁹ C charge on it. Here 'C' stands for coulomb which is the unit of measuring charge.

The atomic number or the total number of protons inside the nucleus of the gold atom is 79.

Therefore, \(\rm Total\ charge\ =\ atomic\ number\times charge\ on\ each\ proton\)

                                        \(\rm = 79\times (1.6\times10^{-19} )\)

                                        \(\rm = 1.26\times10^{-17}\ C\)

So, the nucleus of the gold atom has a total charge of 1.26 x 10⁻¹⁷ C.

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The density of the metal is 8.48 g/mL.

To calculate the density of the metal, we need to use the formula: Density = Mass / Volume. In this case, the mass of the metal is given as 14.8 g. The volume of the metal can be determined by finding the difference in the water level before and after the metal is added to the graduated cylinder.

Find the volume of the metal

The initial volume of water in the graduated cylinder is 25.0 mL, and after adding the metal, the volume rises to 26.9 mL. Therefore, the volume of the metal can be calculated as follows:

Volume of the metal = Final volume - Initial volume

Volume of the metal = 26.9 mL - 25.0 mL

Volume of the metal = 1.9 mL

Calculate the density

Now that we have the mass and volume of the metal, we can plug these values into the density formula to find the density of the metal:

Density = Mass / Volume

Density = 14.8 g / 1.9 mL

Density = 7.79 g/mL

Final result

The density of the metal is 7.79 g/mL.

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+2 is  the most likely charge for a strontium.

Charge often refers to electric charge in chemistry and physics, which is a conserved feature of some subatomic particles that governs their electromagnetic interaction.

An electromagnetic field exerts a force on matter as a result of the physical attribute of charge.

A strontium cation, a divalent metal cation, and a monoatomic dictation are all parts of strontium(2+). It plays the part of a cofactor.

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Answer:

7.5mL of the stock solution

Explanation:

A stock solution is a concentrated solution that is used to make another more diluted solution.

In the problem, the RFC solution is 20% (v/v). That means contains 20mL of RFC in 100mL of solution.

Yo need to prepare 50.0mL of a 3.0% (v/v), solution (3mL of RFC in 100mL of solution). That means you need:

50.0mL solution × (3mL RFC / 100mL solution) = 1.5mL of RFC. These RFC must come from the stock solution

As your stock solution contains 20mL of RFC per 100mL of solution, you will need:

1.5mL RFC × (100mL stock / 20mL RFC) =

Energy from the warm object disperses into its surroundings.  describes the transfer of energy between a warm object and its cooler surroundings

In a system where a warm object and its cooler surroundings are in contact, energy is transferred from the warm object to its surroundings. Heat always flows from a higher temperature region to a lower temperature region, seeking thermal equilibrium. As a result, the warm object loses energy in the form of heat, which disperses into its cooler surroundings until both reach the same temperature. This transfer of energy ensures that thermal balance is achieved between the object and its surroundings.

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Answer:

See Explanation

Explanation:

Wind is a renewable source of energy widely used as a source of energy in order to minimize the pollution that results from some other sources of non renewable energy.

Wind energy has the advantage of;

1)  being a renewable source of energy hence it can be reused and it is not easily depleted.

2)  it does not lead to any form of environmental pollution.

On the other hand, a lot of space is required in order to mount as many windmills as possible in order to generate enough electricity to serve a large area. Thus, the disadvantages of wind energy are;

1) A large expanse of land is required in order to generate a meaningful quantity of energy.

2) The occurrence of wind is inconsistent hence generation of energy is not steady.

Answer:

1)  being a renewable source of energy hence it can be reused and it is not easily depleted.

2)  it does not lead to any form of environmental pollution.

1) A large expanse of land is required in order to generate a meaningful quantity of energy.

2) The occurrence of wind is inconsistent hence generation of energy is not steady.

Explanation: